Westinghouse Electric, the U.S. nuclear unit of Japan's Toshiba, could file for bankruptcy protection as early as Tuesday and is seeking support from South Korea's Korea Electric Power, the Nikkei said on Monday.

A Chapter 11 filing could help Toshiba limit damage from losses at Westinghouse, the report by the Japanese business daily said, without citing sources for its information.

Sources told Reuters on Friday that Toshiba had told its main banks it planned to have Westinghouse file for bankruptcy on Friday, expanding charges related to the U.S. unit this business year to around 1 trillion yen ($9 billion) from its publicly flagged estimate of 712.5 billion yen.

Nikkei said the Westinghouse board would meet as early as Tuesday to decide on a Chapter 11 petition, which it could file the same day. It said the U.S. firm had asked Korea Electric Power Corp, also known as Kepco, to be its sponsor in its bankruptcy reorganization.

Toshiba officials could not be reached outside office hours. Officials answering Kepco's phone said they had no information on the report, referring questions to the press office, which could not be reached outside office hours.